The present invention relates to a hinge for a seat with an adjustable backrest, particularly a power vehicle seat.
Hinges of the above mentioned general type are known in the art. A known hinge includes a stationary hinge member associated with a seat part of the seat, a pivotable hinge member associated with a backrest part of the seat, a pivot axle connecting the hinge members with one another, and an adjusting and fixing device which determines the position of both hinge members relative to one another and is formed as a wobble transmission. The wobble transmission has an eccentric member arranged in a cam region of the pivot axle and rotatable with the latter, and an accumulator which is arranged in the cam region of the pivot axle and adjusts in radial direction the eccentricity of the eccentric member which determines the engagement point of the toothing of the wobble transmission. In a known hinge, the pivot axle has a non-round cam region which for example has at least sectionally a rectangular cross section. This cam region is surrounded by a circular disk provided with an eccentrically arranged recess which is also rectangular at least sectionally and closingly surrounds the cam region on two opposite cam surfaces extending parallel to the eccentricity direction. The surfaces of the recess in the circular disk which are arranged transverse to the eccentricity direction overlap the respective opposite surfaces in the cam region of the pivot axle with play. This play can be bridged by an adjusting member in the sense of an eccentric arrangement of the circular disk on the cam region of the pivot axle. The adjusting member can be formed as an adjusting screw, on the one hand, with which the eccentricity of the circular disk relative to the eccentric portion of the pivot axle can be adjusted. On the other hand, the adjusting member can be composed of a spring element which is arranged between the cam region of the pivot axle and the circular disk surrounding the same in the eccentricity direction. The circular disk which is eccentrically held on the cam region forms the eccentric member which, because of the adjusting member spanned between the cam region and the circular disk, provides a tensioning between the transmission parts supported on the eccentric member and on the centric portion of the pivot axle, as well as provides their bearing points. Thereby, the radial play, particularly in the toothing region, is continuously eliminated. Since, however, the tensioning of the eccentric on the pivot axle remains constant, the tensioning both in the fixed position and during the adjusting movement is available. In particular during the adjusting movement such an eccentric tensioning leads, however, to difficulties in manipulating, so that a relatively high adjusting moment must be applied.